J.-P. Anselme University of Massachusetts at Boston Boston, 02125
I
I
lsodiazomethane Revisited N-aminoisonitriles
Ten years ago,a hrief review in thisJournol discussed the structure and the chemistry of isodianomethane, believed at the time to he nitrilimine (I) (I). Because of the facile transformation of the putative "isodiazomethane" to diazomethane (11) with alkali, Muller (2) had suggested that (I) could reasonably account -
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(I)
(11)
(111)
for the formation of (11) from the reaction of hydrazine with chloroform and alkali, reported earlier by Staudinger and Kupfer (3).I t is of historical interest that these authors'goal was to generate
AH (VI) Reactions
The interconversion of N-aminoisonitrile (N) to diazomethane (11) may he viewed as proceeding via a series of equilibria passing through a symmetrical anion such as (VII). The term "double tautomerism" was suggested to take into account the isocyanogen ( : C = N - N 4 ) by a double Hoffmann (carbylamine) reaction; indeed, in the same paper Staudinger and Kupfer had also proposed the aminoisonitrile (111) as a possible precursor of benzophenone, the alleged product of the reaction of 1.1-diphenylhydrazine with chloroform and alkali. More than 50 years later, it was Ph2NNH2+ [:CCls] (111) Ph&=N=N
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